Zeolites, both natural and synthetic, have been used in a variety of catalytic and adsorptive operations. Most zeolitic materials are porous ordered aluminosilicates having a definite (although often undetermined) crystal structure. The structure may have a number of small cavities interconnected by a number of still smaller channels. These cavities and channels are uniform in size within a certain zeolitic material. The above-mentioned catalytic and adsorptive processes make use of these cavities and channels since by proper choice of zeolite, the zeolite channels will reject some molecules because of their size and accept others.
These zeolites typically are described as a rigid three-dimensional framework of silica and alumina wherein the silica and alumina tetrahedra are linked through common oxygen atoms. The charge balance of the zeolite may be satisfied by inclusion of a proton, metal, or ammonium cation. The catalytic and adsorptive properties of the zeolite may be varied by changing the ions within the zeolite. Conventional ion exchange techniques may be used to change those cations.
Similarly, there are a large number of both natural and synthetic zeolitic structures. The wide breadth of such numbers may be understood by considering the work Atlas of Zeolite Structures by W. M. Meier and D. H. Olson. Many natural zeolites are impossible, or at least quite difficult, to synthesize using the present state of the art. See, Robson, Chem. Tech., (1978), p. 180.
There are a large number of methods for producing zeolitic materials. Many of these synthetic methods utilize mixtures of alumina, silica, a base and water and control the typical zeolite produced by varying the reactant concentration, temperature of reaction, and time of reaction. Other methods of controlling the type of zeolite produced include the use of zeolitic seeds as nucleation centers or organic ammonium salts as "templates" in the reaction mixture.
The use of quaternary ammonium salts as templates or reaction modifiers in the preparation of synthetic crystalline aluminosilicates (zeolites), first discovered by R. M. Barrer in 1961, has led to preparation of a number of zeolites which are not found in nature. For example, U.S. Pat. No. 4,086,859 discloses preparation of a crystalline zeolite thought to have the ferrierite-like structure (ZSM-21) using a hydroxyethyl-trimethyl sodium aluminosilicate gel. A review provided by Barrer in Zeolites, Vol. I, (1981) p. 136 shows the zeolite types which are obtained using various ammonium organic bases as cation. In addition, Breck, Zeolite Molecular Sieves, John Wiley (New York, 1974), pp. 348-378, provides a basic review of zeolites obtained using such ammonium cations in the synthesis thereof.
The zeolite of this invention is produced using an organic ammonium ion (tetraethylammonium) in the synthesis mixture. It has the general chemical composition: EQU (TEA,Na).sub.2 O:(Al,Ga).sub.2 O.sub.3 :3-10 SiO.sub.2.
However, unlike any other synthetic zeolites previously disclosed (See, H. E. Robson, supra) the inventive zeolite has a structure similar to the mineral paulingite. Paulingite is a very rare mineral which is classified as a member of the faujasite group. The mineral was first reported by Kambandke, Amer. Mineral. 45, p. 79, 1960. The mineral's structure has been reported to be complex and its composition to be: EQU (K.sub.2 Na.sub.2 CaBa).sub.76 :(Al.sub.152 Si.sub.525 O.sub.1354):700 H.sub.2 O.
See, Gordon et al, Science 154, p. 1004, 1966.
Clearly, the synthetic zeolite (ECR-18), as disclosed below in greater detail, is not disclosed in the prior art. Similarly, the process for producing ECR-18 has not been previously disclosed.